The present invention relates to a battery power source device providing, on a battery pack including an assembly of single batteries, means for controlling this battery pack to maintain an appropriate operating condition.
Battery power source devices of this type are known in which a plurality of single batteries including of secondary batteries are electrically and mechanically connected in series to constitute battery modules, a required output voltage being obtained by series connection of a prescribed number of such battery modules accommodated in a holder case, these being capable of being freely charged or discharged.
However, since a battery power source device constructed as described above is exposed to severe conditions of use when carried in an electric automobile or hybrid vehicle, maintaining it in a suitable operating condition by controlling the temperature and/or charging/discharging of the battery etc. is demanded. In order to meet this demand, it is necessary to know the condition of the battery power source device itself by detecting the temperature and/or voltage etc. of the battery power source and to report to the external device that uses the battery power source data indicating the operating condition of the battery power source, such as the detected temperature, voltage, current and SOC (State Of Charge), which indicates the amount of electricity stored relative to the battery capacity at 25xc2x0 C.
An object of the present invention is to provide a battery power source device comprising sensors for detecting the operating condition of the battery, means for control in the event of failure, and means for reporting the operating condition to the outside etc.
In order to achieve the above object, the present invention according to a first aspect thereof provides a battery power source device comprising: a battery pack wherein battery modules are formed by connecting in series electrically and mechanically a plurality of single cells constituting secondary cells, a plurality of battery modules being held in a holder case in a three-dimensionally parallel arrangement and a plurality of battery modules being electrically connected in series; cooling means whereby coolant is forcibly made to flow within this battery pack; and means for detecting temperature that detect the temperature of a single or a plurality of battery module units.
The characteristic of a battery depends on its temperature and, in particular in the case of a module in which a large number of batteries are collected, rise in temperature can easily occur, making the operating condition of a battery power source unstable. However, with this construction, temperature detection can be achieved by the means for temperature detection at single or a plurality of battery module units, so temperature management can be performed for single or a plurality of battery module units, making it possible to control charging/discharging and/or the cooling means such that each battery module has a uniform temperature, thereby making it possible to maintain the temperature in the battery pack to a correct level.
The cooling means in the above construction is constituted such as to cause coolant to flow in a direction orthogonal to a longitudinal direction of the battery modules, and the means for temperature detection detect the temperature of battery modules on an upstream side and a downstream side of the coolant flow, and can be arranged to calculate the temperature of the battery modules in an intermediate flow region from the detected temperatures of the battery modules on the upstream side and downstream side, in accordance with a temperature distribution trend within the battery pack. Thus the temperature of the battery modules in the intermediate flow region can be calculated by looking up the detected temperatures the battery modules on the upstream side and downstream side of the coolant flow on the temperature distribution trend, thereby making it possible to detect the temperature at the battery modules in the intermediate flow region without providing temperature sensors there. Consequently, temperature detection of the battery module units becomes possible even though the number of means for temperature detection that are provided is small.
Also, by arranging the cooling means such as to cause coolant to flow in a direction orthogonal to the longitudinal direction of the battery modules, with the means for temperature detection detecting the temperature of a single battery module arranged in parallel in the direction orthogonal with the direction of coolant flow, it can be arranged that the temperature of the other battery modules that are arranged in parallel is calculated in accordance with the temperature distribution trend within the battery pack, and, by finding the temperature distribution trend in the direction orthogonal to the direction of coolant flow beforehand, it is possible to calculate, from the temperature distribution trend, the temperature of the other battery modules in positions that are parallel therewith, by detecting the temperature of a single battery module arranged in parallel therewith in the direction orthogonal to the direction of coolant flow.
Also, by providing a construction such that the cooling means cause coolant to flow in the direction orthogonal to the longitudinal direction of the battery modules and that the means for temperature detection calculate the temperature of other battery modules in accordance with the temperature distribution trend within the battery pack by detecting the temperature of a single battery module; the temperature of the other battery modules can be calculated from temperature detection of a single battery module, by finding the temperature distribution trend at the battery module units within the battery pack.
The temperature distribution trend within the battery pack can be found from the flow rate and temperature of the coolant and data of the charging/discharging mean power; since the temperature distribution trend within the battery pack in which the cooling structure is formed in a fixed condition can be acquired as data corresponding to changes in factors that produce temperature change, the temperature at points other than the reference point can be calculated from the temperature distribution trend by detecting the temperature at a reference point by a sensor.
Also, the means for temperature detection may include a temperature sensor that detects the temperature at a single or a plurality of battery module units; although detection accuracy is raised if temperature sensors are provided for each battery module, taking into consideration costs and the space for their arrangement etc., it is possible to calculate the temperature of battery modules where temperature sensors are not arranged by providing temperature sensors at chief locations, from the previously known temperature distribution trend, using these as reference.
Also, by controlling the operation of the cooling means in accordance with the detection temperature obtained by the means for temperature detection, the temperature within the battery pack can be controlled to an appropriate condition by adjustment of the flow rate and/or flow speed of coolant.
The present invention according to a second aspect thereof provides a battery power source device comprising: a battery pack wherein battery modules are formed by connecting in series electrically and mechanically a plurality of single cells constituting secondary cells, a plurality of battery modules being held in a holder case in a three-dimensionally parallel arrangement and a plurality of battery modules being electrically connected in series; cooling means whereby coolant is forcibly made to flow within this battery pack; means for voltage detection that detect voltage at a plurality of positions arranged on said battery pack; and means for current detection that detect a charging/discharging current of the battery pack.
With this construction, the charging/discharging power of the battery pack can be calculated from the voltage and current detected by the individual means for detection and the charging/discharging power can be calculated even for battery module units from the voltage at a plurality of locations of the series-connected battery modules.
The means for voltage detection in the above construction may include means that detect a total voltage of the battery pack, enabling the charging/discharging power of the battery pack to be obtained in combination with detection of the charging/discharging current.
Also, the means for voltage detection may include means for detecting voltage at a single or a plurality of battery module units; thus the operating condition is detected from the charging/discharging power of a single or a plurality of battery module units in combination with detection of charging/discharging current, and it becomes easy to specify a battery module in which failure occurred, if failure occurs.
The present invention according to a third aspect thereof provides a battery power source device comprising: a battery pack wherein battery modules are formed by connecting in series electrically and mechanically a plurality of single cells constituting secondary cells, a plurality of battery modules being held in a holder case in a three-dimensionally parallel arrangement and a plurality of battery modules being electrically connected in series; cooling means whereby coolant is forcibly made to flow within this battery pack; means for voltage detection that detect voltage at a plurality of positions arranged on said battery pack; means for current detection that detect a charging and discharging current of the battery pack; means for temperature detection that detect a temperature of a single or a plurality of battery module units; and means for determining battery capacity that calculate SOC using the voltage, current and temperature detected by the respective means for detection.
With this construction, the operating condition of charging/discharging power etc. of the batteries can be detected from the voltage, current and temperature detected by the individual means for detection and the SOC of the batteries can be calculated from the state of change of the voltage, current and temperature, making it possible to control the SOC into an appropriate range such that there is no over-discharging or over-charging.
The means for determining battery capacity in the above construction may calculate the SOC of a single or a plurality of battery module units from the voltage of a single or a plurality of battery module units detected by the means for voltage detection, the temperature of a single or a plurality of battery module units detected by the means for temperature detection, and the current detected by the means for current detection; thus, the SOC at a single or a plurality of battery module units can be grasped, so detection of operating condition and/or variability thereof or failure at battery module units can be performed.
Also, the means for determining battery capacity can be constituted such as to calculate the SOC of a single or a plurality of battery module units by looking up the voltage, current and temperature detected by the individual means for detection in a voltage/current data table which is previously found corresponding to each battery temperature; thus, by looking up the individual detection values on the voltage/current characteristics for each battery temperature which were previously found, it is possible to learn the change of SOC at a single or a plurality of battery module units with the interval of detection of the respective detection values, and thereby to detect variation over time of the operating condition of the battery pack.
Also, in the means for determining battery capacity, the temperature of a single or a plurality of battery module units is detected by means for temperature detection and the voltage and current are detected at prescribed time intervals by respective means for detecting the voltage and current, the detected values of voltage and current at each time point are plotted on voltage/current characteristic co-ordinates and the group of voltage/current detection values thus obtained is compared with voltage/current data tables previously found corresponding to each battery temperature; the SOC of a single or a plurality of battery module units can thereby be calculated; comparison is thus effected by plotting the detection values in the voltage/current characteristic for each battery temperature that was found beforehand on voltage/current characteristic co-ordinates, and the SOC at the battery module units can thus be found from this approximation.
Also, the means for determining battery capacity may be arranged so as to control the cooling means in accordance with the voltage, current and temperature detected by the respective means for detection and the SOC calculated by the means for determining battery capacity; thus, control to maintain the battery modules at the appropriate temperature can be performed by controlling the operation of the cooling means in accordance with the detection values which constitute the causes of the change of temperature of the battery modules.
The present invention according to a fourth aspect thereof provides a battery power source device comprising: a battery pack wherein battery modules are formed by connecting in series electrically and mechanically a plurality of single cells constituting secondary cells, a plurality of battery modules being held in a holder case in a three-dimensionally parallel arrangement and a plurality of battery modules being electrically connected in series, positive and negative terminals of this battery pack being connected to an external device that uses this battery power source device; and a relay that opens and closes the connection of said battery pack and the external device.
With this construction, due to the provision of a relay in the charging/discharging circuit, the connection of the battery pack with the external device can be interrupted by interrupting the charging/discharging circuit in the event of failure; thus control to respond to failure can be achieved.
The present invention according to a fifth aspect thereof provides a battery power source device comprising: a battery pack wherein battery modules are formed by connecting in series electrically and mechanically a plurality of single cells constituting secondary cells, a plurality of battery modules being held in a holder case in a three-dimensionally parallel arrangement and a plurality of battery modules being electrically connected in series; cooling means whereby coolant is forcibly made to flow within this battery pack; means for voltage detection that detect voltage at a plurality of positions arranged on said battery pack; means for current detection that detect a charging and discharging current of the battery pack; means for temperature detection that detect temperature of a single or a plurality of battery module units; means for determining battery capacity that calculate SOC using the voltage, current and temperature detected by the respective means for detection; and a relay that opens and closes the connection with an external device that uses this battery power source device to which positive and negative terminals of said battery pack are connected.
With this construction, the battery operating condition in the battery pack and battery black unit can be determined by means of the voltage, current and temperature detected by the respective means for detection and the SOC that is calculated from these and, furthermore, failure is dealt with by means of the relay; management of operation of the battery power source device can therefore be performed in a reliable fashion.
In the above construction, by providing means for preventing rush current in the connection circuit of the relay, damage to the constituent elements of the circuit due to excessively large rush current can be prevented.
Also, by providing means for series circuit interruption that effect interruption at at least one location of the series circuit of the series-connected battery modules, during manufacture and/or maintenance and inspection etc. the series circuit can be interrupted, thereby stopping a hot-line condition of a high voltage circuit.
The present invention according to a sixth aspect thereof provides a battery power source device mounted on an automobile equipped with a motor and generator, said motor being used as running drive source, comprising: a battery pack wherein battery modules are formed by connecting in series electrically and mechanically a plurality of single cells constituting secondary cells, a plurality of battery modules being held in a holder case in a three-dimensionally parallel arrangement and a plurality of battery modules being electrically connected in series, positive and negative terminals of this battery pack being connected to an external device that uses this battery power source device; cooling means whereby coolant is forcibly made to flow within this battery pack; means for voltage detection that detect voltage at a plurality of positions arranged on said battery pack; means for current detection that detect charging and discharging current of the battery pack; means for temperature detection that detect temperature at a plurality of positions set in said battery pack; means for determining battery capacity that calculate SOC using the voltage, current and temperature detected by the respective means for detection; means for transmitting battery condition that output operational condition data of the battery pack to a vehicle control means of said automobile; and a relay that opens and closes a connection circuit of said battery pack with the automobile.
With the above construction, battery power can be used with the battery pack maintained in the correct operating condition by controlling operation of the motor and generator by the vehicle control means, by outputting to the vehicle control means operating condition data of the battery pack from the means for transmitting battery condition, this battery power source device being mounted on a vehicle equipped with a motor and generator.
Also, since the connection of the battery power source device is interrupted by the relay when failure is detected from the respective detection data, damage to the battery power source device or vehicle in the event of failure can be prevented.
By arranging the means for transmitting battery condition in the above construction such that a failure of the battery pack detected by the respective means for detection is output to the vehicle control means, the vehicle control means is able to detect a failure of the battery pack and perform control to cope with this.
Also, the relay being arranged to interrupt the connection circuit of the battery pack with the automobile by the vehicle control means in the event of occurrence of failure, the connection with the battery power source device can be interrupted by the vehicle control means on detection of failure and response to this failure can be performed rapidly.